Expansible mandrel



A. J. MALONEY ETAL 3,174,290

March 23, 1965 EXPANSIBLE MANDREL 2 Sheets-Shet 1 Filed May 15, 1961 INVENTORS 1 BY ALBERT J. llMLa/VEY LflEE/VZO D. ABBEY M.

jrraen/cxi United States Patent M 3,174,290 EXPANSIBLE MANDREL Albert J. Maloney, Fort Lauderdale, Fla, and Lorenzo D.

Abbey, Grand Rapids, Mich, assignors to Canonie Coush'uction Company, South Haven, Mich a corporation of Michigan Filed May 15, 1961, Ser. No. 1tlfl32 3 Claims. (Cl. 6153.72)

This invention relates to an expansible mandrel for driving pile shells and more particularly to an expansible mandrel having an integrally formed central drive shaft provided with shaped openings therein which receive and act directly upon cam means extending from pile shell engaging segments disposed about the central drive shaft.

Numerous expansible mandrel devices have been developed for the purpose of driving thin wall pile shell structures into the ground. The expansible mandrel devices of the prior known art have been complicated structures wherein ancillary cam and cam follower arrangements have been introduced intermediate the drive member or assembly and the expansible members of the particular mandrel unit. In some of the mandrel devices of the prior art, cam extensions have been provided on drive shafts and corresponding co-acting and mating cam follower. extensions have been provided on the expansible members. In other of such mandrel devices, cam follower extensions have been provided on the drive shaft and co-acting mating cam extensions have been provided on the expansible segments. Still other expansible mandrel devices of the prior cited art have utilized complicated linkage cam arrangements between the drive member and the expansible members which co-act to achieve the desired movement of the expansible members in and out of contact of the inner surface of the pile shell. Thus, it is seen that in all of the pile shell driving mandrel devices of the prior known art, the thrust of the drive member is transmitted through cam extension members to the co-acting cam member of the adjacent expansible segments.

The use of such intermediate cam and cam follower assemblies between the drive member and expansible members has resulted in structures that are subject to undesirable bending, twisting, and resultant jamming within the pile shell being riven. In such devices, the thrust imparted by the main body of the drive member is not applied directly, but is transmitted through and applied by radially offset cam extensions provided on the drive shaft.v The resultant stresses on such drive shaft cam extensions under repeated shock conditions result in frequent jamming and damage to the mandrels of the prior art and to the pile shells driven thereby.

In summary, the expansible mandrel structures of the prior known art have thus consisted of structures wherein the main body of the drive member has not directly acted upon the expansible se ments or the cam extensions therefrom to cause their movement toward and away from the drive member in response to corresponding axial movement of the drive member. in the devices of the prior art, the vertically directed force of the drive mem-- ber has been transmitted through radially offset ancillary intermediate cam and cam follower arrangements before it is transmitted to the expansible segments themselves. Thus, bending, torsion, shear, and twist forces are introduced into the structures of the prior art which cause frequent jamming and resultant damage thereto in use. The introduction of cam extensions on the drive members themselves create structures that are inherently damage prone due to the repeated shock use to which these devices are subjected in their operative settings. Experience has shown that such cam extensions provided on 3,.l742fi0 Patented Mar. 23, 1965 the drive members have tended to bend or shear off due to the off-set counter force acting thereon.

It is this oifset characteristic of the force transmission which introduces the high incidence of failures in the devices of the prior known art. This offset force application is particularly troublesome when it is applied through movable cam linkages due to the vulnerability of such linkages to bending, twisting or shearing pressures.

In addition, the use of cam extensions or linkages extending from drive shaft assemblies necessitates, in some cases, the use of drive members comprised of a plurality of mating parts. The segmental nature of such drive members further adds to the complexity of the expansible mandrels of the prior art and contributes to their frequent failures under repeated shock conditions.

The complexity of the intermediate cam and cam follower structures in the devices of the prior art has also made it difficult to reclaim such damaged mandrels from the pile shells in which they have been lodged.

Such complicated structures have generally been diflicult to repair when damaged, difficult to inspect for darnage, and difiicult to lubricate when necessary.

The complexity of such structures has also created problems of transport and storage due to the large number of parts that can be damaged therein during such activity. Generally, misalignment of such complicated mandrels continually occurs and extensive and expensive alignment repairs are necessary to maintain the mandrels in working order. I

A need has therefore existed for an expansible mandrel structure whereby the thrust of the drive shaft is directly applied by the drive shaft body itself to a cam received within the drive shaft body itself. In this manner, the stresses are avoided that are set up within the structures of the prior known art when the thrust force of those drive shafts is borne and imparted by cam extensions provided on and extending from the drive shaft.

A further need has existed for an expansible mandrel which is simple and rugged in construction and which does not involve intermediate complex cam and cam follower structures in operation.

A still further need has existed for an expansible mandrel for driving pile shells which is substantially jamproof in operation and which consists of a central drive shaft member which provides positive direct thrust for selective movement'of expansible segments toward and away from the central drive shaft member.

Yet another need has existed for an expansible mandrel unit which is simple and inexpensive to fabricate, easy to inspect for damage thereto, easy to repair when damaged, and easy to lubricate.

Still another need has existed for an expansible mandrel unit'in which parts thereof may be easily and independently removed for replacement and in which there is case of assembly and disassembly.

Therefore, an object of the invention is'to provide an expansible mandrel structure for driving pile shells which has a central drive shaft adapted to receive and directly act upon cam extensions provided on expansible segments disposed about the drive shaft.

Another object of this invention is to provide an expansible mandrel structure for driving pile shells having a tubular drive shaft that does not utilize cam elements extending therefrom to'impart its thrust to mating cam elements provided on adjacent expansible elements but which imparts its thrust directly to cam elements matingly recevied in passages or shaped openings provided in the tubular drive shaft itself.

A still further object of this invention is to provide an expansible mandrel structure for driving pile shells which has been structurally simplified so as to eliminate cam extension elements on the drive shaft member and thus avoid a major factor causing failures in the devices of the prior known art.

A further object of this invention is to provide an expansible mandrel having a central tubular drive member which has inclined shaped openings or passages in the wall thereof that receive and act upon mating cam extensions of expansible segments disposed about the drive member.

Another object of this invention is to provide an expansible mandrel unit which is easy and inexpensive to fabricate, easy to visually inspect for damage, and easy to disassemble for repair or replacement.

Another object of this invention is to provide an expansible mandrel unit which is adapted to permit collapse of the expansible segments against the central drive member to a minimum total outside diameter clearance hitherto not obtainable in expansible mandrels of the prior art.

Yet another object of this invention is to provide a rugged simple, trouble-free structure capable of high production and economical maintenance.

Other objects and advantages found in the construction of this invention will be apparent from a consideration of the following specification in connection with the appended claims and accompanying drawings.

In the drawings:

FIGURE 1 is a fragmentary sectional schematic view of the expansible mandrel illustrating the expansible segments in their fully retracted position against the central drive shaft with the cam plate extensions fully within the drive shaft body and showing in phantom-line a portion of a pile shell within which the expansible mandrel is inserted.

FIGURE 2 is a sectional schematic view taken on line A-A of FIGURE 1 to more clearly illustrate the relative positioning of the drive shaft, the cam plate extensions and the expansible segments when the expansible mandrel is in the full retract or collapse position.

FIGURE 3 is a fragmentary sectional schematic view of the expansible mandrel illustrating the expansible segments in their fully expanded position away from the central drive shaft and showing in phantom-line a portion of the pile shell with the expansible segments thereagainst.

FIGURE 4 is a sectional schematic view taken on line BB of FIGURE 3 illustrating the relative positioning of the drive shaft, the cam plate extensions, and the expansible segments when the expansible mandrel is in the fully expanded position.

FIGURE 5 is a top view of one of the expansible segments illustrating the transverse arcuate configuration thereof and showing the uppermost of the vertically spaced cam plates extending therefrom and the arcuate stabilizing extension along the bottom edge of the expansible segment.

FIGURE 6 is a fragmentary side view of one of the expansible segments illustrating the elongate configuration thereof and showing the plurality of vertically spaced downwardly inclined cam plates extending therefrom.

FIGURE 7 is a fragmentary elevational view of one of the expansible segments illustrating the vertically spaced downwardly inclined cam plates extending therefrom and the stabilizing extension along the bottom edge thereof.

FIGURE 8 is a top view of the tubular drive shaft member illustrating the stabilizing collar segments provided at the upper edge thereof.

FIGURE 9 is an elevation view of the, hollow drive shaft illustrating the plurality of downwardly and inwardly inclined passages or shaped openings provided through the wall thereof.

In, general, this invention consists of an expansible mandrel 12 for driving pile shells. The expansible mandrel 12 is provided with an elongate central longitudinal drive shaft member 13 having a plurality of inclined vertically spaced and radially disposed shaped openings therein in the form of slots or passages 14. The slots or passages 14 are adapted to matingly receive cam plate members 15 extending from the expansible segments 16 disposed about the central drive shaft 13.

As shown inFIGURES 1 through 4, the cam plates 15 of the expansible segments 16 slidingly engage the in clined slots or passages 14 provided in the drive shaft 13 so that relative axial movement of the central drive shaft 13 selectively causes movement of the expansible segments 16 toward and away from the central drive shaft 13.

As shown in the top view of FIGURE 5 the expansible segments 16 are provided with a transverse arcuate curvature so as to facilitate the engagement thereof with the inner surface of a pile shell. A plurality of vertically spaced cam plate extensions 15 are provided along the inner surface of expansible segments 16. The elongate configuration of the expansible segments 16 is specifically shown in FIGURES 6 and 7. In addition, the vertically spaced cam plate extensions 15 are provided at periodic intervals along the entire length of expansible segments 16, also shown in FIGURES 6 and 7. The cam plate extensions 15 are relatively narrow in width and are inclined to extend downwardly and'outwardly from the expansible segments 16 .at an angle of approximately 30 from the vertical axis thereof. The upper surface of the cam plate members 15 is curved so as to matingly' and slidingly engage the upper surface of the slots or passages 14 provided in the drive shaft member 13.

As shown in the drawings, the expansible segments 16 are provided with arcuate stabilizing extension members 17 along the bottom edge thereof so as to extend outwardly therefrom. The upper surface of the stabilizing extension member 17 is sloped to correspond with the inclination of cam plate elements 15 thereabove and is adapted to engage the chamfered bottom edge of the drive shaft plug member 18 provided in the bottom of the drive shaft member 13.

As will be hereinafter described, the drive shaft mentber 13 is axially moved in a downward direction to act; upon the cam plate extensions 15 of the expansible segments 16. As the cam plate extensions 15 are acted upon by the drive shaft 13, the bottom edge of the plug 18 also similarly acts upon the sloped surface of stabi lizing extension members 17. In this manner, a constant and continual force is applied along the entire length of the expansible segments 16, causing them to always move outwardly or inwardly in a vertical position. This prevents bending or displacement of the expansible seg ments 16 out of the vertical position and, hence, jamming or damage of the mandrel 12 is less likely to occur. 7

As shown in FIGURES 8 and 9, the preferred embodi= ment of the drive shaft member 13 is of tubular or pipe-like construction. Rows of vertically spaced iiiclined slots or passages 14 are radially disposed around the drive shaft member 13 and are positioned to matingly receive the cam plate extensions 15 of the expansible segments 16 that are disposed about the central elongate drive shaft 13. Therefore, inasmuch as the preferred embodiment of the invention utilizes four expansible segments 16 disposed about the drive shaft 13 (as shown in FIGURES 14), four rows of vertically spaced slots or passages 14 are located through the drive shaft 13 at intervals. Thus, there are clusters of four inclined slots or passages 14 found at predetermined positions along the longitudinal axis of the drive shaft member Stabilizing collar elements 19 are circumferentially dis.-

posed about the upper edge of the central drive shaft member 13, as shown more specifically in FIGURES 8 and 9 and generally in the drawings. The collar e1ements 19 are provided with an upwardly and outwardly extending lower surface having the same slope or angle as the angle of the passages 14, the stabilizing extensions 17 and the cam plate extensions 15. When the drive shaft 13 moves axially downward, the collar elements 19 act against the upper inside edge of the expansible segments 16. Thus, the thrust of collar elements 19 cooperates with the thrust of the slots or passages 14 upon the cam plate extensions 15 and the thrust of the lower edge of the drive shaft plug 18 upon the stabilizing extensions 17 so as to exert a constant, continual, and equal force along the entire length of expansible segments so as to insure that, when the expansible segments 16 are forced outwardly, as shown in FIGURE 3 and FIGURE 4, they are not displaced from the vertical. Thus, the possibility of damage to mandrel unit 12 or pile shell 20 is greatly diminished. It is with the scope of the invention to utilize a unitary collar element about the upper edge of the drive shaft 13 instead of the individual arcuate collar sections shown in the drawings.

A driving head assembly 21 having a slotted plug extension is inserted into the upper end of the tubular drive shaft 13 and is retained therein by the pin 22, as shown in FIGURES l and 3. Commonly known actuating means are utilized to drive and retract the expansible mandrel within and from the pile shell and are not shown or described herein.

The material utilized to fabricate the various components of the expansible mandrel are metallic in nature and must be of such metals that are commonly known to be able to withstand the repeated shock blows to which the mandrel is subjected in driving pile shells.

It is also within the scope of the invention to vary the inclination or slope of the passages 14, the cam plates 15, collar members 19 and stabilizing extension 17 so as to vary the movement of expansible segments 16 as desired for any particular pile shell driving application.

Operation In operation, the expansible mandrel 12 is lowered into the pile shell to be driven. At this point, the expansible segments 15 are in their fully retracted position against the central driven shaft 13, as shown in FIG- URES l and 2. The cam plate extensions 15 are posi tioned through the slots or passages 14 that are provided in the drive shaft member 13. In this full retract position, the bottom surfaces of the cam plate extensions 15 are in contact with and are supported by the bottom surfaces of the slots or passages 14. In this position, the cam plate extensions 15 are substantially completely within the body of the drive shaft 13. Thus, the expansible segments 16, in their normal free position, are suspended from the drive member 13 and normally assume the full retract position against the drive shaft 13. This is particularly beneficial for storage or transport purposes because, as shown in FIGURES 1 and 2, the expansible mandrel 12, in the full retract position, 0ccopies the smallest space and is in its most compact position. It is pointed out that bumping or jarring of the expansible mandrel 12 during storage or transport will only serve to urge the expansible segments 16 into closer engagement against the central drive shaft 13 in their full retract position.

It is also seen that damaged expansible segments 16 may easily be removed for repair by merely lifting them outwardly and upwardly away from the drive shaft 13 so that the cam plate extensions 15 are withdrawn from the slots or passages 14 of the drive shaft 13 itself. There are no complicated cam linkages or cam followers in structural locking engagement with cam extensions so as to require extensive disassembly of the entire expansible mandrel before an expansible segment can be removed.

In use, a driving force is applied to the driving head assembly 21 and the drive shaft member 13 is axially displaced in a downward direction. This downward axial movement of the drive shaft 13 causes the upper surfaces of the slots or passages 14 to come into actuating contact with the upper surfaces of the respective cam plate extensions 15 that are inserted therethrough. Thus, the thrust of the drive shaft 13 is directly imparted to the cam plate extensions 15 by the drive shaft body itself. As the thrust of drive shaft 13 continues and the drive shaft 13 continues to be axially displaced downwardly, the upper surfaces of the slot or passages 14 co-act with the upper surfaces of the cam plate extensions 15 to urge the expansible segments 16 outwardly, away from the drive shaft 13 and into driving engagement with the inner surface of the pile shell 20, as shown in FIG- URES 3 and 4. Simultaneously, the stabilizing collar elements 19 are co-acting with the upper edges of the expansible segments 16. The lower chamfered edge of the drive shaft plug 18 is also co-acting with the stabilizing extensions 17. In this manner, a continual, constant and equal thrust is maintained along the entire length of the elongate expansible segments 16 so that, while the expansible segments 16 are urged outwardly away from the drive shaft 13, the longitudinal axis of each expansible segment 16 always remains in the vertical position, thus avoiding stresses that might cause jamming with resultant damage to the expansible mandrel 12 or the pile shell 20 which is being driven.

When an upward and withdrawing force is applied to the drive shaft 13, the bottom surfaces of the slots or passages 14- of the drive shaft 13 come into contact with the bottom surfaces of the cam plate extensions 15. As the drive shaft 13 continues its upward axial movement, the bottom surfaces of the slots or passages 14 coact with the bottom surfaces of the cam plate extensions 15 to cause the expansible segments 16 to move inwardly, toward the drive shaft 13 and out of contact with the pile shell 20. It is again pointed out that during the upward axial movement of the drive shaft 13, the thrust of the drive shaft 13 is imparted to the cam plate extensions 15 directly by the drive shaft body itself without the necessity of having the thrust force of the drive shaft 13 transmitted through radially offset drive shaft cam or cam follower extensions. The retraction of the expansible segments 16 is greatly facilitated because the tendency of the expansible segments 16 is to slide inwardly toward the central drive shaft 13 to their normal rest position against the drive shaft 13 with their cam plate extensions 15 fully inserted through the slots or passages 14 into the hollow portion of the drive shaft itself.

As shown in the drawings, the slots or passages 14 are slightly larger than the cam plate extensions 15 inserted therethrough so as to facilitate their co-action in response to the upward or downward axial movement of the drive shaft member 13.

It is thus seen that a highly utilitarian expansible mandrel has been provided which is of such simple rugged construction and concept so as to avoid the problems encountered in the use of mandrel devices of the prior known art. The provision of inclined shaped openings in the body of a pipe-like drive shaft member itself which receive and coact with similarly inclined cam plate extensions provided on expansible segments disposed about the drive shaft member results in a trouble-free expansible mandrel having a minimum of co-acting independent parts.

The simplicity in concept and design has resulted in an expansible mandrel which is easy and comparatively inexpensive to fabricate when compared to the complicated devices of the prior art.

The instant invention also constitutes an expansible mandrel which is capable of collapsing to a minimum total outside clearance not possible in other mandrel devices of the same or similar fully expanded outside clearance. This greater collapsing ability is possible due to the shaped opening concept of the central drive shaft member which permits storage of the cam plate extensions 15 fully within the drive shaft body itself when the mandrel is in the full retract or collapse position. Thus, the resulting greater clearance between the collapsed mandrel and the pile shell permits insertion and removal of mandrel unit without becoming fouled due to small distortions of the pile shell.

It is further seen that the collapsing and expanding arrangementof the instant expansible mandrel invention is positive due to the fact that the thrust is imparted by the drive shaft body itself and hence, the mandrel structure is rigid and shock resistant.

Other advantages are that the design of invention is such that visual inspection of the mandrel is easy, in that all parts are readily seen from the quarter points between the expansible segments. The simplicity of operation and design also permits rapid and low-cost repair maintenance. Thus, there is less down time on the job, with resultant labor cost savings. In addition,'preventive maintenance and lubrication is also greatly facilitated in the use of the instant expansible mandrel.

Various modifications of the invention may be made without departing from the principle thereof. Each of the modifications is to be considered as included in the hereinafter appended claims unless these claims have by their language expressly provided otherwise.

Having thus set forth the nature of our invention, we claim the following:

1. In an expansible mandrel for driving pile shells, the combination comprising: a central tubular drive shaft, said tubular drive shaft provided with a plurality of downwardly and inwardly inclined passages therethrough having inclined upper and lower surfaces; a plurality of longitudinally extending pile shell engaging segments disposed about said tubular drive shaft; a plurality of downwardly and inwardly inclined cam plates having correspondingly inclined upper and lower surfaces provided on said segments, said inclined upper and lower surfaces of said cam plates adapted to slidingly engage said inclined upper and lower surfaces of said passages so as to selectively cause movement of said segments toward and away from said tubular drive shaft in response to axial. movement of said tubular drive shaft.

2. In an expansi-ble mandrel as claimed in claim 1 inv which each of said plurality of pile shell engaging segments comprises an elongate, transversely arcuate, pile shell engaging segment; a plurality of vertically spaced, downwardly and inwardly inclined cam plates extending from said segment so as to operatively engage said inclined passages of said tubular drive shaft; and a stabilizingextension member provided along the lower inside edgeof said segment, said stabilizing extension member having a downwardly inclined upper surface extending from said segment which co-acts with the lower edge of said. drive shaft during downward axial movement of said drive shaft so as to cause movement of said segment away from said drive shaft.

3. In an expansible mandrel as claimed in claim 1' where the drive shaft comprises: an elongate hollow drive shaft, said drive shaft defining a plurality of vertically spaced, radially disposed, downwardly and inwardly in-- clined passages so as to operatively engage said inclined cam plates therethrough; and stabilizing collar elements provided at the upper outer edge of said drive shaft, each of said stabilizing collar elements having an upwardly and outwardly extending surface which co-acts with the upper edge of its respective expansible segment during downward axial movement of said drive shaft so as to cause movement of said segment away from said drive shaft.

References Cited by the Examiner UNITED STATES PATENTS 757,767 4/04 Poor 61-53.72 2,840,993 7/58 Caudill 6153.72 2,928,252 3/60 McKee 61-5372 2,977,770 4/61 Hoppe 6153.72

FOREIGN PATENTS 54,674 12/90 Germany.

234,896 5/11 Germany.

EARL J. WITMER, Primary Examiner.

JACOB L. NACKENOFF, JACOB SHAPIRO,

Examinem. 

1. IN AN EXPANSIBLE MANDREL FOR DRIVING PILE SHELLS, THE COMBINATION COMPRISING: A CENTRAL TUBULAR DRIVE SHAFT, SAID TUBULAR DRIVE SHAFT PROVIDED WITH A PLURALITY OF DOWNWARDLY AND INWARDLY INCLINED PASSAGES THERETHROUGH HAVING INCLINED UPPER AND LOWER SURFACES; A PLURALITY OF LONGITUDINALLY EXTENDING PILE SHELL ENGAGING SEGMENTS DISPOSED ABOUT SAID TUBULAR DRIVE SHAFT; A PLURALITY OF DOWNWARDLY AND INWARDLY INCLINED CAM PLATES HAVING CORRE- 